Power storage devices can employ controls that perform simple functions to charge and discharge power to improve performance and longevity of the device. Improving the efficiency of batteries is of particular importance in view of the move to electric powered automobiles, and the adoption of portable computing technologies such as cellular telephones and portable data devices (i.e., music player, PND, notebook computers). Accordingly, there is a need to provide solutions to extend the performance of existing power storage technologies.
In electrochemical energy storage devices (i.e., batteries, fuel cells, and other such devices for transforming the chemical energy of a fuel into electrical energy) the overall performance of the device can be dependent on the mass transport to and away from the sites where the electron transfer reaction occurs. In general, mass transport can be impeded by effects such as polarization, memory effects, and hysteresis effects of a discharge. An improvement in any of these effects, or in any combination of these effects, can improve the mass transport within the power storage device, and accordingly, improve the performance of the power storage device.
It has been established that in many catalytic reactions, the rate of the reaction can be determined by processes occurring in close proximity to the interface. These processes can take place either before or after the catalytic reaction occurs. For example, an increase in the diffusion rate of a reacting species away for a catalytic site can increase the overall rate of the catalytic process. It is generally known that these interfacial processes can be advantageous for chemical reactors, gas masks and any other similar devices.
The implementation of interfacial processes can be extended to power storage devices. As is described below, it is possible to create or destroy interfacial catalytic sites via fast electron or ion transport. According, the control of such interfacial processes can impact the mass transport in electrochemical energy storage devices and provide for improved performance of the devices.